CEACAM5 and gastric cancer: Some studies have reported that HOX transcript antisense RNA (HOTAIR) [9], LINC00152 [10], and LIFR-AS1 [11] were upexpressed in GC tissue, while C5orf66-AS1 [12] and lnc-GNAQ-6:1 [13] were downexpressed in GC serum, and the exosomal lnc-GNAQ-6:1 exhibited a more favored ROC than traditional biomarkers such as serum carcinoembryonic antigen (CEA), cancer antigen 19-9 (CA19-9), and carbohydrate antigen 72-4 (CA72-4) [13].